The structural and molecular plasma membrane changes of granulosa cells during follicle development, vulation, and luteinization will be investigated. Two aspects of membrane differentiation will be probed: (1) the appearance and organization of plasma membrane receptors for FSH and LH on rodent and porcine granulosa cells and (2) the development, function, and fate of granulosa cell gap junctions. Receptor ontogeny will be studied by characterizing the peptide composition of plasma membranes isolated from granulosa cells at various stages during follicle development. The disposition and fate of cell surface hormone-receptor complexes will be determined by fluorescene and electron microscopy using derivatized hormone preparations. Morphometric methods will be used to quantitate plasma membrane and gap junction surface area changes during follicle growth and ovulation. Ovarian a gap junctions will be isolated and analyzed by electron miscroscopy, gel electrophoresis and other techniques of lipid and protein chemistry.